Hair trigger burglar alarm

ABSTRACT

A burglar alarm for detecting the unauthorized opening of a door or window in a building comprises a unitary, compact structure for attachment of the alarm with an actuating cable or chain connected in a manner to trigger the alarm upon very slight opening of the door or window. A horn and a can of pressurized fluid are mounted adjacent each other on a frame with a connection for the flow of pressurized fluid from the can to the horn when a normally closed valve is opened. A spring is biased in a manner to cause opening of the valve when the spring bias is released. A lever normally holds the spring in biased position with an arrangement whereby the slightest pull on the lever by the flexible connection to the door or window causes release of the spring and actuation of the horn.

United States Patent Gantt Sept. 12, 1972 [54] HAIR TRIGGER BURGLAR ALARM [72] Inventor: Kenneth T. Gantt, 4132 East 144th St., Cleveland, Ohio 44128 [22] Filed: July 26, 1971 [21] Appl. No.: 165,470

[52] US. Cl. ..116/86, 74/2, 116/112 [51] Int. Cl. ..G08b 13/08 [58] Field of Search ..116/86, 85, 89, 94, 100, 112, 116/81, 101; 222/39; 7 4/2; 70/432 [56] References Cited UNITED STATES PATENTS 60,897 1/1867 Johnson ..1 16/81 301,862 7/1884 Chase ..1 16/81 2,570,438 10/1951 Flagge et a1. ..'...116/81 2,793,651 5/1957 Gomez ..116/112 X 3,185,127. 5/1965 Chedister ..116/86 3,244,137 4/1966 Garvey ..116/1 12 X 3,391,367 7/1968 Messick ..116/101 X 3,451,369 6/1969 Leve et al ..116/86 L '1 IIIII I ll V ll ll Att0rneyBaldwin, Egan, Walling & Fetzer [5 7] ABSTRACT A burglar alarm for detecting the unauthorized opening of a door or window in a building comprises a unitary, compact structure for attachment of the alarm with an actuating cable or chain connected in a manner to trigger the alarm upon very slight opening of the door or window. A horn and a can of pressurized fluid are mounted adjacent each other on a frame with a connection for the flow of pressurized fluid from the can to the horn when a normally closed valve is opened. A spring is biased in a manner to cause opening of the valve when the spring bias is released. A lever normally holds the spring inbiased position with an arrangement whereby the slightest pull on the lever by the flexible connection to the door or window causes release of the spring and actuation of the horn.

6 Claims, 12 Drawing Figures PAIENTEDSEP 12 m2 SHEET 1 [IF 2 INVENTOR.

KENNETH T. GANTT BY gfiNE 5 sum 2 or 2 FIGII INVENTOR.

KENNETH T. GANTT ATTORNEYS PATENTEB SEP 12 m2 HAIR TRIGGER BURGLAR ALARM Many burglar alarms are known, many of which are quite complicated and many of which require the supply of electrical energy for their operation. An object of the present invention is to provide a simple device with parts which are small in number and simple in operation and requiring only a can of pressurized fluid to insure that the horn of the device operates when necessary.

Other objects and advantages of the present inven tion will be apparent from the accompanying drawings and specification and the essential features thereof will be set forth in the appended claims.

In the drawings,

FIGS. 1 and 2 are respectively top plan and side elevational views of a first embodiment of the device shown in its unoperated position;

FIGS. 3 and 4 are .respectively top plan and side elevational views of the same showing the parts in operated position; v

FIG. 5 is a back elevational view of the upper portion of FIG. 2 taken from the opposite side;

FIG. 6 is a fragmental sectional view taken along the line 6-6 of FIG. 5;

FIG. 7 is a fragrnental elevational view slightly enlarged taken along the line 77 of FIG. 4;

FIGS. 8, 9, and 11 are elevational views taken in the position of the upper portion of FIG. 5 but showing other arrangements of the spring restraining lever, FIGS. 8 and 9 showing a first modification, in spring restraining and releasing positions respectively, while FIGS. 10 and 11 show a second modification with the spring restraining and releasing positions respectively; while FIG. 12 shows an elevational view of a second embodiment of the invention with parts broken away in section to more clearly show the operation of the parts.

Referring now to the first embodiment shown in FIGS. 1 through 7, a box-like frame 15, open only at the rear, has attached thereto a bracket 16 which supports a can 17 of pressurized fluid, a preferred embodiment of which is a container of Freon. This'can has a dischargeneck 18 through which flow is controlled by a normally closed valve 19 which is of the type which opens by tilting, one form of which isshown in U.S. Pat. No. 2,704,622, granted Mar. 22, 1955 to Jack W. Soffer. This valve is normally closed when the neck 18 is in an axially straight position as shown in FIG. 2. Firmly secured at the upper end of the neck 18 is a projecting portion 20a of horn body 20 so constructed and arranged that when the pressure fluid passes through valve 19, neck 18 and the projection 200, it causes the horn to sound.

Referring to FIGS. 2 and 7, an actuating member 21 is mounted for reciprocation in a tubular member 22 which is secured to the frame by the threads at 22a. The lower end of the member 21 is connected at 21a to the outer end of the horn 20. A helical spring 23 embraces the member 21 and is held between cap 24 and nut 25 normally in a biased compressed condition. The amount of such biasing depends upon the threading of the thumb nut 26 on the upper end of the member 21.

Restraining means is provided on the frame for holding the spring 23 normally in its biased position. This is here shown as comprising a lever 27 having an opening near one end through which the member 21 passes freely and held in the position shown in FIGS. 2 and 5 for holding the spring 23 biased by means of a needle support 28 which is fixed to the top wall of the frame 15. Means is provided as at opposite ends of the lever 27 where the holes 27a are seen for the attachment of a flexible cord or chain in such a manner that when the door or window is slightly opened by a burglar, the lever 27 is pulled in a manner to dislodge it from then needle point support at 28. In the form shown in FIGS. 1 and 3, openings 27b are provided on opposite sides of the point support at 28a which represents the position of the top of the needle 28. The openings 27b are closely adjacent this point so that a very slight movement of the lever 27, upon opening movement of the door or window, causes the upper opening 27b, as shown in FIG. 3, to register with the needle support 28 which permits the lever 27 to drop to the position shown in FIG. 4 which allows the thumb nut 26 and the actuating member 21 to drop from the position of FIG. 2 to the position in FIGS. 4 and 7, impelled by the compression of spring 23. This causes the horn 20 to be tilted downwardly at the right-hand end as seen in FIG. 4 which causes a tilting of the neck 18 of the can 17 which causes the valve 19 to open as indicated by the arrow at A in FIG. 4. This causes the horn to make a sound.

It should be understood that the frame 15 may be mounted on a door or window with a flexible member such as a cable 29 secured to a wall of the building in such a manner that opening movement of the door or window will cause the lever 27 to move from the position of FIGS. 1 and 2 to the position shown in FIGS. 3 and 4. The parts are so arranged that this movement is very small for which reason I have named this device a hair trigger burglar alarm. On the other hand, the alarm mechanism herein disclosed may be mounted on the wall of the building such as a door frame, nd the flexible member 29 would then be connected with the door or window to operate the alarm.

Shown in FIG. 6 is means for easily attaching this device to a door 30.. This comprises a plate 31 which fits in the open back of the frame 15 and is secured to the door by screws 32. The plate 31 has an upturned tongue portion 31a parallel to the main portion of the plate 31 which is threaded at 33 to receive a threaded bolt 34 which passes through asuitable opening 35 in the front wall of frame 15 and is limited in its inward movement by a flange 34a on the bolt. Extending crosswise of the frame 15 is a back plate member 36 which is held by screws 37 in suitable ears on the end walls of the frame 15. As will be understood from FIG. 6, the member 31 is first secured to the door by the screws 32, after which the frame member is positioned with the back plate 36 between tongue 31a and plate 31, after which the bolt 35 is threaded into position to hold everything firmly. The dot-dash line 38 shown in the various views indicates a cover which is usually provided to screen the burglar alarm structure so that the device appears to give a more pleasing appearance.

A second form of this invention is shown in FIG. 12 where the frame 15', the tubular member 22', cap 24', thumb nut 26', needle support 28, and back plate 36' are quite like those already described in the first embiased in a restrained position with helical spring 23 held Compressed by adjustment of the thumb nut 26'. Here a can 17 of pressurized fluid is supported on the frame by a connector 39 which is threaded into a collar 40 at the lower end of the tubular member 22, and at its opposite end is threaded at 41 into. the discharge neck 18' of the can 17. A check valve 42 normally closes the discharge through neck 18' and a plunger 43 is reciprocatably mounted in a central bore of the connector member 39. A pointed projection 43a at the lower end of the plunger lies in a position to cause opening of the valve 42 upon downward movement of the plunger as seen in FIG. 12. The upper end of the plunger at'43b is in position to be engaged by the lower enlarged head 21a of the actuator member 21 when spring 23 is released.

A flow connection 44 communicates between then neck 18' of the can 17' and the horn This horn has a flexible diaphragm 45 which forms the lower wall of a chamber 'seenin FIG. 12 as having an upper wall 46 through which a central small opening 46 is provided.

Upon release of pressure fluid through the connecting pipe 544, the diaphragm 45 is caused to vibrate to produce the noise from horn 20'.

In this embodiment, the restraining means includes a lever 27 quite similar to the earlier described lever 27 which has an opening near one end through which the actuating member 21' freely passes, and an intermediate portion of the lever normally. rests on the needle point support 28 as mentioned in connection with the needle support 28 in the first embodiment. Shown only in dotted lines in FIG. 12 are representations of openings in the lever 27 like those described at 27b of the first embodiment so that slight movement of the lever 27 will cause the point support 28' to pass through one of the openings 27b, thus permitting lever 27' to drop from its full line position of FIG. 12 to the dot-dash position which permits 'the actuator member 21 to move downwardly impelled by spring 23', causing opening of valve 42 so that pressure fluid passes across the pipe 44 to blow the horn 20'.

Fastened in one end of the lever 27' is a chain 47 which may extend off of the door 30 to the door jamb 48 upon which is secured a locking member 49 which has a keeper 49a which normally engages the end link of the chain 47 as shown in FIG. 12. This is a known type of locking device wherein the home owner, desiring to enter the house, opens the door 30' just sufficiently to reach in and unlock the lock 49 to release the chain 47 so that the alarm will not sound when is opened a little further.

In FIGS. 8 through 11, there are shown some variations of the support approximating a point as first indicated at 28 in FIG. 5. These modifications might be utilized either in connection with the first or second embodiment but will be described here in connection with the first embodiment as shown in FIG. 5. The lever 270 passes freely over'down, post 50 which is fixed in the top wall of the frame 15. The other end of the lever has an opening through which the actuating member 21 freely passes. The support here is provided by a wedge 51 of plate material which is connected by a flexible cord 290 in such a fashion that upon a slight opening movement of the door or window, to which the burglar alarm is attached, the wedge 290 is pulled out of its supporting position of FIG. 8 to a free position in FIG. 9, which permits the lever 270 to move down releasing the restraint on spring 23 so that the actuator 21 is caused to move downwardly and cause the alarm to sound as described in connection with the first embodiment.

In FIGS. 10 and 11, the lever 271 rests flat on the top wall of the frame 15 so as to be slidable longitudinally of its own length. The actuating member 21 here passes through a slot 272 in the lever, a portion of which has walls 273 which project upwardly for a very short distance so that in one position of the lever 271, shown in FIG. 10, the nut 26 is held upwardly by resting upon the projections 273. Upon very slight opening of the protected door or window arranged to cause endwise movement of the lever 271 in one or the other direction of the arrows shown in FIGS. 10 and 11, the thumb nut 26 slides off the projections 273 permitting the actuator member 21' to move downwardly to cause the sounding of the horn. The modifications of FIGS. 8 through 11 may be applied to eith'erthe first or second embodiment of this invention. a

What is claimed is: Y'

1. A burglar alarm adapted for mounting on or adjacent a closing device adapted normally to close an opening in a building such as a door or a window, comprising a unitary structure including a frame for at? tachment of the alarm in a fixed position, an assembly of a horn and a can of pressurized fluid having a discharge neck and a flow connection communicating between said can neck and said horn mounted on said frame, there being a normally closed valve in said can neck preventing discharge of said pressure fluid, an actuating member on said frame operatively connected to cause opening of said valve, spring means mounted on said frame operatively associated with said actuating member and biased in a direction to cause opening of said valve, restraining means on said frame normally holding said spring means biased including a support approximating a point in engagement with said restraining means, and meansattached to said restraining means in a manner to be pulled from its holding position by opening movement of said closing device, whereby slight opening movement of said closing device will cause release of said restraining means, whereupon said spring will open said valve and cause said horn to sound.

2. A burglar alarm as defined in claim 1, wherein said restraining means comprises a lever, and said support is a needle point on said frame maintaining said lever in a position holding said spring means biased.

3. A burglar alarm as defined in claim 1, wherein said restraining means comprises a lever, and said support is a wedge inserted between said lever and said frame maintaining said lever in a position holding said spring means biased.

4. A burglar alarm as defined in claim 1 wherein said restraining means comprises a lever, and said support is a projection on said lever effective between said frame and said actuating member for holding said spring means biased, and said projection movable to an ineffective position by a pull on said attached means caused by opening movement of said closing device.

5. A burglar alarm as defined in claim 1, wherein said actuating member is a plunger, means on said frame type and normally closed when said neck is in axially straight position, said actuating member is connected to said horn at a point spaced from said neck connection, said neck is axially straight in biased position of said spring means, and said spring means when released from said restraining means causing said horn to tilt said valve to open position. 

1. A burglar alarm adapted for mounting on or adjacent a closing device adapted normally to close an opening in a building such as a door or a window, comprising a unitary structure including a frame for attachment of the alarm in a fixed position, an assembly of a horn and a can of pressurized fluid having a discharge neck and a flow connection communicating between said can neck and said horn mounted on said frame, there being a normally closed valve in said can neck preventing discharge of said pressure fluid, an actuating member on said frame operatively connected to cause opening of said valve, spring means mounted on said frame operatively associated with said actuating member and biased in a direction to cause opening of said valve, restraining means on said frame normally holding said spring means biased including a support approximating a point in engagement with said restraining means, and means attached to said restraining means in a manner to be pulled from its holding position by opening movement of said closing device, whereby slight opening movement of said closing device will cause release of said restraining means, whereupon said spring will open said valve and cause said horn to sound.
 2. A burglar alarm as defined in claim 1, wherein said restraining means comprises a lever, and said support is a needle point on said frame maintaining said lever in a position holding said spring means biased.
 3. A burglar alarm as defined in claim 1, wherein said restraining means comprises a lever, and said support is a wedge inserted between said lever and said frame maintaining said lever in a position holding said spring means biased.
 4. A burglar alarm as defined in claim 1, wherein said restraining means comprises a lever, and said support is a projection on said lever effective between said frame and said actuating member for holding said spring means biased, and said projection movable to an ineffective position by a pull on said attached means caused by opening movement of said closing device.
 5. A burglar alarm as defined in claim 1, wherein said actuating member is a plunger, means on said frame mounting said plunger for reciprocation into and out of engagement with said normally closed valve, and a seal between said last named means and said plunger preventing leaking of pressure fluid from said flow connection.
 6. A burglar alarm as defined in claim 1, wherein said horn is substantially rigidly connected near one end to said can discharge neck, said valve is of the tilt-opening type and normally closed when said neck is in axially straight position, said actuating member is connected to said horn at a point spaced from said neck connection, said neck is axially straight in biased position of said spring means, and said spring means when released from said restraining means causing said horn to tilt said valve to open position. 